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A. G. WESTAD AND E. L. HA GG.

SIEVE FOR WOOD PULP PLANTS.

APPLICATION FILED OCT. l5. 19l8.

Patented Aug. 12, 1919.

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wem wzj r anon-vote wnsranann ERIK LUDVIG uses, or Hunsros, NORWAY, ASSIGNORS TO AKTIESELSKABET e. naiarnann, or cnarsrrama, noaway.

' SIEVE FOR WOOD-PULP PLANTS.

Specification of Letters Patent.

Patented Aug. 12,1919.

Application filed October 15, 1918. Serial No. 258,258.

To all whom it may concern:

Be it known that we, ABRAHAM GRoN- VOLD WESTAD and ERIK LUDVIG Hiicc, both subjects of the King of Norway, of Huns- :t'os, Norway, have invented certain new and useful Improvements in Sieves for VVood-Pulp Plants; and we do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a part of this specification.

As is well known the pulp in wood pulp plants is conveyed from the sand catcher to the sieves, where the last and most accurate sorting operation takes place.

When the pulp arrives at the sleves 1t 1s suitabl diluted so that it flows evenly downward, but during the sieving operation the remaining pul gets thicker and thicker owing to all t e impuritles, which do not pass through the sieves.

Finally on the two last sieves there remains a considerable amount of coarse stufi,

splints and the like, which accumulates byand by so that the sieves can not be utilised to their full capacity. Usually a spuling hose is at hand by means of which the last sieve is spuled at intervals, but then the pulp as well as the coarse stuff and the splints are removed thus causing an extensive waste of material.

It has been proposed to arrange a scraper which rotates slowly and scrapes the last sieves, but this arrangement is unsatisfactory, as the scraper will take away the valuable pulp together with the coarse stuff and also with this scraping arrangement the s1eve plates are easily filled up,sothatthey are of no use. It has also been proposed to arrange spuling tubes oscillating above the sieving plates, and the present invention has for its object a articular arrangement of such spuling tubes by means of which an eflectlve cleaning of the sieveplates is effected.

This result is attained by arranglng the oscillating spuling tubes in such cooperating relation to each other and so locating the et holes of the same that they continually act 1 to move the pulp in the same direction, the

pulp from one end or the effective area of 53 a spuling tube being carried farther in the latter is connected by means of a crank arm to shaft 5 mounted above the sieve plates 6 by means of brackets 7 fastened on one sideof the sieve frame.

Shaft 5 carries on its free end a water tube 8, which is connected by means of flexible hose 11 to a stationary water tube 12, and the free lower end of the tube 8 carries a horizontal tube 9 parallel to the sieve and perpendicular on the longitudinal axis of the same. The length of tube 9 corresponds to the breadth of the sieve. A. plurality of shafts 5 are located above the sieve each shaft being oscillated exactly contrary to the adjacent shafts" by means of rods 10 connected with the crank arms of each shaft alternately above and below the axis of 0s H cillation.

The cross tubes 9 at the lower end of each oscillating tube 8 are provided'with a plurality of et holes in such a manner that the jets are all directed in the same'way along the sieve plate.

; During the oscillation of the jet tubes I each row of jets will cover a certainarea of the sieve plate and the relative position of the oscillating tubes are so chosen, that adjacent jet areas slightly overlap in order that all the stufi driven by means of one oscillating jet tube to a certain part of the .sieve plate is taken up by the next jet tube and carried farther 1n the same direction.

I laim- 1. In combination with a sieve for wood-- ul pu ing tubes located above the sieveplates and having their jet holes directed the same way along the sieve plate, and means for oscillating said spuling tubes lengthwise of and above the sieve plates, the sieve areas spuled by the jets of each. tube overlapping slightly, whereby the stuff carried to a certain part of the sieve by means of one spuling tube is carried farther in the same direction by means of the next spuling tube.

plants and the like, a plurality of 2. In combination with a sieve for wood pulp plants and the like, a plurality of 0s-' cillatory shafts located above and parallel to the sieve plates, water tubes carried b said shafts having the form of an inverted flexible tubes connecting the shank ends of said tubes to a water supply, the cross pieces of the tubes being provided with jet holes approximately parallel to the longitudinal axis of the sieve, and means for oscillating said shafts lengthwise of the screen in opposite relation to each other, whereby the sieve areas spuled by the jets of each tube overlap slightly and the stufi carried to a certain part of the sieve by means of one spuling tube is carried farther in the same direction ABRAHAM GRllNVOLD WESTAD. ERIK LUDVIG HKGG.

Witnesses:

L. PETERSEN, RUB LF ANnERsEN. 

